itch.io

If you really do want to access external resources in Decker, then it is sort of possible, and you could look at The Forbidden Library for some examples,  but with what you're doing there's also the problem of whatever you're accessing would need to be rendered in Decker - so like if it's a full blown interactive website you're trying to get to it's really only going to work as a separate link.

… and I hate using Google Slides and Canva + I like the aesthetic of Decker.

It’s possible to copy Decker’s aesthetic in other presentation software. Given what you want to accomplish, I’d build everything in Decker (import images with the cool 1-bit black and white dithering, keep the pixel fonts, etc.) and screenshot the cards to import into the more robust software of your choosing.

Also, Millie mentioned about the Forbidden Library (Danger Zone). It’s for HTML decker projects only, but if you (or someone you know) is savvy with JavaScript, you could have buttons or cards within Decker launch iframes containing the desired websites positioned over the Decker project’s canvas. It would look like Decker was embedding the websites, but that’s outside the scope of Decker itself.